Tag Archives: solar panel

Maximum power

I’ve been having some difficulty with my battery slowly running down over time, in spite of installing a second solar panel. I’d been advised to install a maximum power point tracking (MPPT) charge controller.

Solar panels don’t produce consistent power at all voltages. If you connect them directly to your battery their voltage is pulled down to around 12V, but many produce more power at around 20V. In fact, the ideal voltage varies with the light conditions.

An MPPT controller has a voltage converter to allow the panels to stay at a higher voltage, and it has a processor that adjusts that voltage to track the maximum power point.

But beware, many Chinese suppliers are sticking the letters MPPT on everything to get sales. Some controllers have even changed from being MPPT to not because manufacturers have economized on components. This is all fraudulent, of course, but hard to police.

YouTubers to the rescue. Amateur enthusiasts on YouTube like to review gadgets, and these helpful videos by Adam Welch reviewed a low cost controller.

I now have one of these installed on Tammy Norie and it appears to be doing the job nicely. I’ve been able to connect my two panels in series rather than parallel so that they’re producing over 12V even in quite low light. The controller seems to hold the combined voltage at about 48V in sunlight, suggesting that my NASA panels have a maximum power point around 24V.

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I haven’t been able to get an accurate current measurement. My meter seems to upset the controller, which may indicate that it’s doing something quite delicate. Time will tell if this scheme works well and I will report back.

In the meantime, this is the eBay listing I used. Worth a try for £25 I thought.

Update 2017-09-19: So far this is not working very well and I don’t suggest buying this until until I’ve had a chance to do more experiments.

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Filed under battery, electrics

Little jobs roundup, 2017-08

I usually make posts about big things I’ve done, and not many about the hundreds of little jobs I do on Tammy Norie. I thought I’d start a series of occasional posts noting these, and if anyone wants more details they can ask in the comments.

The 30-year-old mushroom vent over the heads compartment cracked. The plastic looked like old ceramic. Replaced, although I don’t much like the quality of the new one. I’ll keep a look out for a stronger replacement.

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I bought a CTek battery charger before going to the Netherlands in 2015. When I got there, it didn’t work! What’s more, when I tried to return it to the shop, they’d closed down, and their parent company had gone bankrupt. CTek eventually agreed to send me a new one directly, but it has been in its box for two years, untested. In a rare stay at a marina, I decided to test and install it.

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Here it is installed below the main electrical panel in what would be the engine compartment on a bigger boat. Below it you can see the gas alarm (below head level when sleeping) and a big circuit breaker. The solar panel regulator promises to prevent overloads, and the every switch on the panel has a circuit breaker too, so I’m pretty well protected from shorts. I have a better main breaker for the panel when I re-make it.

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At the back of the compartment you can see water-tight plastic boxes with spares and parts inside. I label them using tape and a big marker pen, so that I can pull out the right box from deep in the compartment.

I shortened the plastic tube I put around my yard parrel to prevent chafe. I can now peak up a few more degrees.

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I finally stuck down my second solar panel. It’s been attached with duct tape for the past year. In spite of that, it’s never tried to escape overboard. I only really need a second panel because I installed a fancy main radio with GPS and AIS alarms, so I that I could sleep more soundly on offshore passages. I don’t use this radio much inshore.

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I fixed yet another leak. This one was through the bolts fixing the pushpit rail foot. This was a good test for butyl tape, which I’m favouring over Sikaflex these days. It’s as easy to handle as Blu-tack and seems very effective.

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Tammy Norie’s bilge is too small to fit a proper electric bilge pump. I bought a very cheap submersible Chinese pump from eBay, connected it to some narrow hose, and ran that alongside the main hose, then through an existing hole and into the engine well.

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This pump is not going to save any lives. It takes a few minutes to empty even Tammy’s tiny bilge, but it’s nice to be able to press a button. And the installation interferes with nothing else.

My old tiller pilot got wet inside, corroded, and stopped working. I sold the remains at a boat jumble. My uncle then gave me an old one he had in the attic. The same model. Great, except that it didn’t come with the mounting bar. Dad suggested the thread on the mounting socket might be a pipe thread. He was right! It’s a 20mm thread as used on 15mm copper pipe fittings. A quick visit to a hardware shop and I have a new mount.

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The mast hinge sleeve has a habit of walking around the mast until it jams up. At one stage, I had to use a mallet to free it up so that I could lower the mast. So I’ve drilled and tapped a screw hole to keep it in place.

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This revealed a probem further up the sleeve. There were some quite deep gouges in the aluminium near the boom.

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The culprit? Countersunk screw heads sticking up from the strip of material on the boom designed to prevent chafing the mast! Fail.

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I’ve tightened up these screws on all the strips, and increased the depth of the recess in some cases. It might be better to use some other kind of fixing. If you look carefully at this picture you can see that the screws at the end have been pulled inwards, as if the mast strip has shrunk, or the boom has grown.

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The rivets holding the handle to my Captain Currey rigging knife came apart, and the handle fell off. So I replaced them with nice machine screws in new recesses, oiled the handle, and sharpened the blade on my stone too.

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Lastly, I’ve been gradually working my way around the woodwork, rubbing off the old brown paint and some of the UV damage, then treating the wood with oil. You can see the contrast here. Imagine when it’s all done!

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I’ve done the same to the tiller, but unfortunately I discovered that under the paint the tiller is not a very beautiful piece of wood. So that will be getting some new paint, and perhaps I’ll get hold of a bit of hardwood and whittle a new tiller on passage.

That’s all for now. I hope you enjoyed seeing the small ways in which Tammy is improving.

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Wiring diagram

I’ve made this diagram (which is also on the “About” menu of this blog) in case anyone’s interested.

wiring diagram

wiring diagram

I’ll try to keep it up to date if anything changes. The only addition I’m expecting this year is a fixed VHF radio, probably a Standard Horizon GX2200 because it has built-in GPS and AIS, and so can provide me with a ship proximity alarm without any further equipment.

Here’s a slightly out-of-date picture of where the switch panel and most of the connections are located, under the bridge deck. The main difference now is that I have an integrated digital volt/ammeter that is much more responsive.

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The solar panel

I’ve just written a reply to a thread asking about solar panels on the YBW forums, and I thought it’d be worth reproducing here for anyone interested.

I have a Nasa 20W through a CMP12 solar regulator to my Platinum SD685L 75Ah leisure battery, from which the main drain is the tiller pilot. I use the tiller pilot a lot as I’m usually solo, and the panel keeps up with the drain on a sunny day, and generally has no difficulty keeping up with the instruments and lights. My VHF is handheld and charged from the main battery occasionally.

I haven’t hooked up a sensitive ammeter and done the calculations yet. However, I do have one of these volt/ammeters with the ammeter in line with the battery and can highly recommend it. (I know then the solar panel is keeping up because the ammeter reads zero drain.) I filled the back of the meter with silicone electronic potting compound to keep the electronics from getting damp.

The solar panel was held down by duct tape on the aft locker for a lot of last year, but now it’s stuck down with a generous bead of Sikaflex. Nasa recommend this as a method. It suits me as it’s removable and doesn’t involve making holes in the boat, and especially not putting screws in the deck core, which you should never do.

Here’s a picture of the solar panel in its new position.  This spot is almost never in shadow.

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I just have to trim those Sikaflex blobs and clean off the old duct tape glue.

The wiring isn’t final either. I’ve looked at a few deck glands but there’s a fairly large connector on the other end of the wire, and I’d like to avoid cutting it off or making a hole in the boat. The wire actually squeezes nicely down the hinge side of the locker, so I might just fix it down (more Sikaflex) more or less where you see it, reinforce where it might chafe in the hinge, and then use some self-adhesive cable fixings inside to connect it forward.

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Filed under battery, Equipment, Repairs and Modifications

First tour of Tammy Norie

On the way from Shotley to West Mersea I recorded this little tour of Tammy Norie. Things mentioned:

  • boat layout
  • autopilot
  • solar panel
  • sheeting system
  • deck fittings
  • deck locker contents
  • sail trim
  • mysteriously long burgee halyard
  • oars
  • cockpit drains
  • Coromandel versus Corribee topsides and cabin layout
  • headlining
  • Plastazote® insulation and buoyancy foam
  • mystery flies

There’s plenty more to show for another time.  Let me know if you have anything you particularly want to see or know about.

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2014-08-13 · 07:53